| Glass | Acrylic | |
| Clarity | Glass has as a slight green tint. Most of the time people do not notice it, however it becomes noticeable when you place it next to an acrylic tank. Special glass is available that lacks some of the metal content that causes the green tint. In the industry, this type of glass is often referred to as Starphire or Star Glass. | Acrylic is clear for the most part. Some claim that the acrylic yellows over time which is possible considering it's exposure to UV active lighting. Most plastics will show yellowing as a result of UV exposure. Depending on the material, it may be a matter or months or a matter of years before such discoloration becomes noticeable. |
| Weight | Weight is an issue with glass. It is extremely heavy, and even a medium sized tank (55-120 gallons) will require two or more people to move. We recommend that tanks larger than 200 gal. to be made of acrylic, due to the prohibitive weight of glass tanks. | Acrylic is roughly half the weight of glass. It is ideal for large aquariums. |
| Durability | Unless you are in an earthquake zone, glass tanks are very sturdy, and do not scratch nearly as easily as acrylic tanks. Once they scratch however, the damage is more or less permanent. There are ways to remove scratches from glass, but none are cost effective. | Acrylic
tanks can scratch VERY easily. You must be careful when you are cleaning
it to avoid scratches, and also be careful what types of inverts to buy
since some will gouge the surface. Many sessile invertebrates prefer to
burrow into acrylic than the live rock they came in on. Scratch removal
kits are available and do work well. Some kits can be used under water so
there is no need to take the tank apart to polish the glass. Large tanks, particularly long tanks have a tendency to bow outward as time goes on. |
| Insulation | Glass is not a particularly good insulator, it transfers heat readily, so heating costs will be higher. | Acrylic tanks insulate heat 6 times better than glass tanks. This is great in the winter when you are trying to heat the tank. |
| Cost | For tanks smaller than 200 gallons, glass is the less expensive option. | Smaller acrylic tanks are more expensive than comparably sized glass tanks. Larger tanks are more economical. |